#452: Cooper Clinic staff radiologist John Cannaday talks CT scans and radiation

healthylivingradio's Podcast

John Cannaday, M.D., a staff radiologist at Cooper Clinic discusses two studies reported in the December issue of the Archives of Internal Medicine, calling on physicians to limit CT Scans due to the risks associated with radiation exposure. The study headline read "Commonly performed CT scans are exposing patients to far more radiation than previously thought and in doses that could cause tens of thousands of cancers a year." In the two studies, the authors call on physicians to limit radiation exposure to patients.

Dr. Cannaday reports that CT scans are used regularly at Cooper Clinic as a tool in evaluating cardiovascular health, and diagnosing coronary artery disease and blockage. The technology over the past decade has dramatically improved - through CT scans it's possible to take a noninvasive three dimensional tour of the torso.

In the first study, a team (lead by Dr. Rebecca Smith-Bindman) at the University of California, San Francisco, collected data from 1,119 patients who received 11 types of CT scans in four area hospitals. The level of radiation exposure in the CT scans varied widely within and across the hospitals, with an average variation that was 13-fold. For example, the dose of radiation for a multiphase abdomen-pelvis CT scan ranged from 6 to 90 millisieverts, with an average dose of 31 millisieverts.

In the second study, Amy Berrington de Gonzalez and her team (from the National Cancer Institute's Division of Cancer Epidemiology and Genetics) estimated that 29,000 future cancers could be related to scans performed in 2007, and that these cases could result in about 14,500 deaths.

From a consumer standpoint, the more exposure we have to radiation, the higher the potential risk of cancer. Dr. Cannaday says that we are not able to free ourselves from radiation, the average background radiation is 3 millisieverts. Scan ranges less than 100 millisieverts are considered low exposures. The team at the Cooper Clinic have aggressively trained to run these tests with the lowest possible exposure possible.

The average exposure for a multiple slice of the heart to look for calcium scoring is approximately .9 millisieverts, so less than 1 millisievert. For the coronary CT antiogram which is a more extensive test, Cooper Clinic routinely performs this test with a millisieverts score of 2 or less. The test is more involved when looking at coronary bypass patients, and Cooper Clinic performs this test for 2.5 millisieverts or less.

Dr. Cannaday believes patients should talk with their physician about the radiation exposure of any test, and to ascertain if there are alternative ways to get the results without non-ionizing radiation, for example through MRI or ultra sound. Any exam in the imaging department needs to be tailored to the question being asked, and minimizing radiation exposure should be a consideration.

Patients need to keep in mind that scans are a tremendous tool in diagnosing cardiovascular, abdominal, chest and head diseases. While we need to be aware of radiation exposure, Dr. Cannaday hopes that studies like these don’t scare people away from having tests they may genuinely need for managing their overall health.

ReferenceStudies Quantify Cancer Risks From CT Scans

Jill Turner is VP of Operations for Cooper Concepts, the company that markets Cooper Complete nutritional supplements, and oversees the Cooper Wellness Program, where individuals come to live at Cooper for a week at a time to focus on living a healthy life. Jill regularly contributes information to the Cooper blog. Email [e-mail] or call 972-560-3262 with your questions and comments.